A powerful array processor to be attached to our existing VAX 11/780 computer is requested. This instrument will be dedicated to research in medical imaging and image processing. Specifically, four projects are proposed, two each in digital radiology and nuclear medicine. In digital radiology, the goal of the proposed research is to deblur subtraction angiograms by using sophisticated image processing algorithms, thereby facilitating the visualization of atherosclerotic lesions in the coronary arteries. Two distinct processing algorithms will be investigated. Both of these algorithms are well known in the image processing leterature, but have not yet been applied to large medical images for lack of sufficient computer power. The nuclear medicine projects have as their goal earlier detection and more accurate characterization of small neoplasms. In one of these projects, three-dimensional images will be reconstructed from coded-aperture data. This approach allows true tomographic reconstruction without any motion of the detector or aperture. The other nuclear medicine project involves automated feature extraction and pattern recognition of liver scans. In addition, it will include an attempt to optimize the design of nuclear imaging systems for most accurate extraction of the relevant features.